The present invention relates to the field of foundry operations and more particularly to the field of castings wherein conveyors are utilized to move sand molds to various stations along a casting line. In greater particularity, the present invention relates to a casting line utilizing a weight and jacket about the sand molds and a pouring line as well as a discharge line. In still further particularity, the present invention relates to a conveyor system wherein the pouring line and discharge line are at different elevations and to the mechanism for handling castings and molds on said conveyor.
The art of casting metal objects in sand molds is ancient. Numerous advances have been made in the art including the automation of the process and the integration of conveyors into the process. Certain elements of casting are invariable, thus one of the problems is to adapt the environment in which the castings are made to fit the available resources. One increasingly evident factor is cost. As the cost per square foot of building space increases, the casting line becomes more expensive. Likewise, the greater cost of installation yields a reduced likelihood of adoption of a particular line. Numerous patents have addressed the problems associated with the space limitation as well as the time limitation. That is to say, a conveyor has to have sufficient length to allow a molten casting to solidify before the casting can be discharged, thus a continuously operated conveyor has a finite number of incremental movements between the time the casting is poured and the casting is discharged. The cumulative dwell time of a casting on the incremental positions must equal the length of time required before the casting can be discharged. Where space is not a problem, the casting line could be any length needed, however, space is generally a problem.
It is an object of the present invention to provide an automated casting line having minimal floor space requirements and minimal installation requirements in terms of site preparation.
Another object of the invention is to provide a system, which permits ready access to the various stations for maintenance and repair.
These and other objects of the invention are provided by an offset conveyor system wherein a lower section of the conveyor is positioned adjacent a pouring station where molten metal is poured into weighted and jacketed sand molds. Molds are transported on carriers along the lower section from a mold loading station to a weight and jacket placement station to the pouring station. After pouring, the carrier with jacketed mold is moved upwardly to an offset upper conveyor section that is parallel the lower section and may overlap the lower section partially. Molds are transported in an opposite linear direction relative to the lower section, to a weight and jacket removal station and to a mold dump station, where the sand mold and casting are removed from the conveyor. The carrier is returned to the lower conveyor section to receive another mold. The weight and jacket removed from the upper section is placed on a mold on the lower section, therefore only a minimum number of weights and jackets are used. The mold carriers may be dimensioned to carry sand molds in side by side relation, thus castings may circulate more than one circuit on the conveyor to permit additional cooling and solidification if necessary.